
This scientic publication in digital format is a continuation of the Printed Review: Legal Deposit pp 196802ZU42, ISSN 0378-7818.
    Rev. Fac. Agron. (LUZ). 2024, 41(3): e244127 July-September. ISSN 2477-9407.
6-6 |
Table 4. Thermodynamic parameters for red and yellow onion.
T
(°C)
ΔH
(kJ mol
-1
)
Allium cepa L.
ΔS
(kJ mol
-1 
K
-1
)
Allium cepa L.
ΔG
(kJ mol
-1
)
Allium cepa L.
Noam Centrum Noam Centrum Noam Centrum
60 76,9
138,9
-48,3
-486,1
93,0
30,1
70 76,8
138,8
-48,5
-486,3
93,5
30,6
80 76,7
138,7
-48,8
-486,6
94,0
31,1
However,  no  statistically  signicant  disparities  were  found  in 
the values of the entropy dierential (∆S) for Allium cepa L., variety 
Noam (p-value = 0.832) and Centrum (p-value = 0.828) when varying 
the drying temperatures (60, 70, and 80) ºC, for a condence level 
of 95 %. However, when comparing between varieties, statistically 
signicant disparities (p-value = 0.000) were found in the ∆S, being 
−48.4 ± 0.3 kJmol
-1
K
-1
 for the Noam variety and −486.4 ± 0.2 kJ.mol
-
1.
K
-1
 for the Centrum variety, as detailed in Table 4. Therefore, it can 
be observed that the values obtained for ∆H, ∆S are lower than those 
recorded by Braga da Silva et al., (2019).
In  the  Gibbs  free  energy  dierential,  no  statistically  signicant 
disparities were found for Allium cepa L., variety Noam (p-value 
=  0.923)  and  Centrum  (p-value  =  0.885)  when  varying  the  drying 
temperatures (60, 70 and 80) °C,  for  a  condence  level  of  95  %. 
However, when comparing between varieties, statistically signicant 
disparities  (p-value  =  0.000)  were  found  in  the  Gibbs  free  energy 
dierential, being 94.0 ± 0,1 kJ.mol
-1
  for the Noam variety and 30.1 
± 0,2 kJ.mol
-1
 for the Centrum variety, as detailed in Table 4. These 
results are lower than those published by Braga da Silva et al. (2019) 
on pretreated Piper aduncum leaves (108.955 y 113.889 kJ.mol
-1
), and 
higher than those reported by Quequeto et al. (2019) on laurel leaves 
(53.038 kJ.mol
-1
).
Conclusions
The Midilli model was determined to be the most appropriate 
model to represent the experimental data on the drying process of 
Allium cepa L., applicable to the Noam and Centrum varieties 
regardless of variations in drying temperature. Furthermore, increasing 
the temperature during the drying process  signicantly  reduced  the 
time required to remove water from both varieties of Allium cepa L. 
and  caused  an  increase  in  the  eective  water  diusion  coecient. 
However,  this  increase  in  temperature  did  not  signicantly  aect 
the values  of  enthalpy dierential, entropy, and Gibbs free energy, 
demonstrating that these thermodynamic properties remain relatively 
stable under the drying conditions studied.
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